There are many existing telephone loops that, due to their length, difficulty of access, or circuit makeup, are expensive to maintain. It is quite often the case, when a repairman visits a subscriber premises following a trouble report, that it is found that the telephone loope tests out satisfactorily and the compliant was caused by no one to answer the telephone, was due to a temporary equipment overload, or the telephone equipment, other than the loop itself, on the subscriber's premises was at fault. Thus, the repairman has made a trip to an extreme end of a telephone exchange for naught. In recent days, it is becoming more and more prevalent for subscribers to install and maintain their own on premise equipment, e.g., TWX, PBX, telephone equipment (hand sets) and the like. Thus, reports of "telephone" trouble by a subscriber to a telephone company are beginning to be mixed bag, i.e., troubles regarding equipment to the telephone company is responsible for (mainly the telephone loop) and troubles that the subscriber is responsible for (on premise equipment). The hereinafter disclosed invention allows telephone company personnel to make the distinction as to where the reported trouble is and whose responsibility it is, without a repairman leaving the maintenance depot.